Game Theory Applications: Lecture Notes Course Website http://www.citi.umich.edu/u/galka/games Galina Albert Schwartz Department of Finance University of Michigan Business School 04.16.01 and 04.18.01 Lecture Notes in Game Theory 1 Summary of last two lectures Auctions: Dixit, chapter 15 Types of Auctions Winner’s Curse Vickrey’s Theorem Auction Design Summary of the Course 04.16.01 and 04.18.01 Lecture Notes in Game Theory 2 Auction Design: Types of Auctions Four Major Considerations – Types of Auction Settings – Bidding Types – Pricing Schemes – Valuation Methods 04.16.01 and 04.18.01 Lecture Notes in Game Theory 3 Types of Auction Settings English Auction – history: used by major auction houses, Cristie’s and Sotheby’s – Major Feature: Ascending Price Dutch Auction – history: used in tulip trading – Major Feature: Descending Price 04.16.01 and 04.18.01 Lecture Notes in Game Theory 4 Bidding Types – Sealed bid auction »Advantage: makes collision more difficult – Open-outcry auction »advantage: casts additional information to the bidders about the object value 04.16.01 and 04.18.01 Lecture Notes in Game Theory 5 Valuation Methods Two major methods [types of objects] – private (subjective valuation) » different bidders value the object differently » example: collectibles – common (public, objective value) » All bidders have the same value, [but might have different estimates of this value] » example: oil fields 04.16.01 and 04.18.01 Lecture Notes in Game Theory 6 Pricing Schemes First Price Auction – no true price revelation – price is shaded (lower than the true value) Second Price Auction – price is revealed truthfully under `reasonable` conditions – [proven by Vickrey (1996 Nobel Price)] 04.16.01 and 04.18.01 Lecture Notes in Game Theory 7 Winner’s Curse When the Winner’s Curse is a problem – common value auctions – high level of uncertainty of the object value How to alleviate the Winner’s Curse – Use Second Price Auction 04.16.01 and 04.18.01 Lecture Notes in Game Theory 8 Revenue Equivalence Theorem `reasonable` conditions are: – bidders are risk-neutral – object is of a common value – bidder’s estimates of this value are independent ==> Revenue Equivalence Theorem holds: All types of auctions on average yield the same outcome (i.e. the same profit [surplus]) 04.16.01 and 04.18.01 Lecture Notes in Game Theory 9 Departures from the Theorem’s Conditions & Auction Design Assume that bidders are risk-averse & object is of a common value & bidder’s estimates of this value are independent – Then 04.16.01 and 04.18.01 Lecture Notes in Game Theory 10 Departures from the Theorem’s Conditions & Auction Design Assume that bidders are risk-neutral & their valuation estimates are positively correlated – Then 04.16.01 and 04.18.01 Lecture Notes in Game Theory 11 All-Pay Auctions All bidders pay their bids, but only one [or several] get the object – example: athletic competitions Optimal bidding strategy in all-pay auctions: Use of Mixed strategy 04.16.01 and 04.18.01 Lecture Notes in Game Theory 12 Some Other Considerations Reserve Price of the object Information disclosure Why e-Bay is a second price auction Auctions and Stock market: are there any similarities? Auctions and LBOs: are there any similarities? 04.16.01 and 04.18.01 Lecture Notes in Game Theory 13 Government Objective Function Duality of Government Objective – to maximize the auction revenues – to maximize the government revenues that auction brings [auction revenue & future tax revenues from the corporations who submitted the winning bids] – to maximize economic efficiency of provision of the goods related to auction in question – to maximize the total surplus of the specific auction [a sum of government revenues [seller’s surplus], corporate profits [buyer’s or bidder’s surplus], and consumer surplus 04.16.01 and 04.18.01 Lecture Notes in Game Theory 14 Can Everyone be a Winner? Example of California Energy Crisis – I promise a 6 times drop in the price of electricity in CA [three years ago] – why the academicians are silent? Example of British Government Auction Policy – Klemperer [Oxford] designed the system for the Government [ seller] – he also consults the companies [bidders] 04.16.01 and 04.18.01 Lecture Notes in Game Theory 15 Summary of Auctions I auctions can be » English (ascending) & Dutch (descending) » open outcry & sealed bid » first price & second price » common value & private value Auction Theory major results » Revenue Equivalence Theorem » Vickrey’s mechanism (truthful price revelation via second-price sealed bid auction) 04.16.01 and 04.18.01 Lecture Notes in Game Theory 16 Summary of Auctions II What matters for auction design – bidder’s (buyer’s) features: » risk attitude (risk-neutral or risk-averse) » their valuation of the object(independent or correlated) – Seller’s objective function » short-term surplus maximization » long -term considerations » economic efficiency (government is a seller) – Information Structure 04.16.01 and 04.18.01 Lecture Notes in Game Theory 17 Summary of the Course We learned: – Dixit, chapters: 1 – 5, 15, 16 + some extras – Lewis, chapters: ALL (the entire book) Major Lesson from our studies: – common sense works – `common` theory works better, because it » aggregates the common sense, » structures it, and » makes it from the art into a science 04.16.01 and 04.18.01 Lecture Notes in Game Theory 18